UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

 WASHINGTON D.C., 20460 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION

2 Nov 2010 

MEMORANDUM 

SUBJECT: Correction to Parameters “Task Duration” and “Surface Area”, and Verification 

of “AaiH” for EPA’s 4 October 2010 Science Review of the AEATF II Mop 

Human Exposure Monitoring Study. MRIDs 48210201, 48231201, and 

48231901 

 

FROM: Tim Leighton, Environmental Scientist 

Antimicrobials Division 

TO: Nader Elkassabany, PhD, Chief 

Risk Assessment and Science Support Branch 

Antimicrobials Division 

REF: Selim, S., and Taylor, M. (2010) A Study for Measurement of Potential Dermal 

and Inhalation Exposure During Application of a Liquid Antimicrobial Pesticide 

Product Using Bucket and Mop Equipment for Cleaning Indoor Surfaces. 

Unpublished study prepared by Golden Pacific Laboratories, LLC, under Project 

No. AEA03, Report No. 070265. 2116 p. (MRIDs 48210201, 48231201, and 

48231901) 

Leighton, T. (2010) Science Review of the AEATF II Mop Human Exposure 

Monitoring Study. MRIDs 48210201, 48231201, and 48231901. Memorandum 

dated 4 October 2010 to Nader Elkassabany. 25 p. 

This memorandum corrects and verifies three study parameters reported in the cited EPA 

Science Review of the human exposure mop study submitted by the Antimicrobial Exposure 

Assessment Task Force II (AEATF II). The attached tables report the corrected values for the 

task duration and surface area. My science review of 4 October 2010 used the correct AaiH; no 

changes have been made in the AaiH. Therefore, the dermal and inhalation exposure data as 

presented in the original EPA science review were not affected by these changes. Appendix A of 

my science review for the alternative proportionality analysis used the incorrect sampling time, 

and will need to be re-run. However, this analysis was an alternative review and not presented in 

the science review itself or at the HSRB meeting. 

Page 1 of 6 
Data Errors Identified

Dr. William Popendorf, a member of the Human Studies Review Board, noticed that there were 

inconsistencies between values of sampling duration and the amount of active ingredient handled 

(AaiH) reported in the study report (MRID 48210201, Appendix K) and in Table 2 of EPA’s 4 

October 2010 science review. These exceptions were called to EPA’s attention via e-mail from 

Dr. Popendorf on November 1, 2010. 

EPA has reviewed the values in question, has consulted with the Study Director and the QA 

Analyst at Golden Pacific Laboratories, and has determined that the AEATF’s study report 

correctly reports sampling duration and AaiH for each subject in Tables 12, 13, and 14 (MRID 

48210201 pp. 109-111). Table 84 of the same report (MRID 48210201 p. 181), however, 

attributed sampling times to the wrong subjects, as a result of confusing the subject number 

identification and the monitoring event assignment. That the error occurred in the transcription 

of data from Tables 12, 13, and 14 to Table 84 was confirmed by the study’s QA Analyst. 

In preparing Tables 2, 3, and 4 attached to EPA’s 4 October 2010 science review, EPA matched 

the (incorrect) sampling times from Table 84 to the surface area mopped as reported in Tables 

12, 13, 14 of the study report. This resulted in EPA incorrectly matching the surface area 

mopped to the MEs. The AEATF study report correctly reported the surface areas. EPA’s 

summary statistics, however, were based on Tables 12, 13, and 14, and are correct. 

Finally, the Study Director has reported to EPA that Appendix K included erroneous summary 

values of AaiH for subjects M8, M7, and M24. Again the values for these 3 subjects reported in 

study Tables 12, 13, 14 are correct. No AaiH errors were brought forward into EPA’s analysis of 

the data. 

Impact of the Identified Errors

The following consequences of the identified errors have been identified: 

(1) Tables 2, 3, and 4 of the EPA Science Review memo must be corrected. Corrected tables 

are attached below, with revisions highlighted in yellow. 

(2) Surface area of floor mopped was not used in the statistical analysis, and EPA presented 

only summary statistics for the surface area mopped to the HSRB. Since the actual 

surface area mopped values were correct, and the error was in the incorrect attribution of 

these correct values to particular subjects, the summary statistics were unaffected, the 

summary information presented to the HSRB was correct, and no corrections are needed. 

(3) Task duration was used only in an alternative analysis of proportionality between dermal 

exposure and time. These results were summarized only in the statistical Appendix A to 

the EPA Science Review. EPA will re-run the alternative analysis and update Appendix 

A. EPA presented only summary statistics for the sampling time to the HSRB. Again 

since the actual values were correct, their incorrect attribution to subjects did not affect 

Page 2 of 6 
Page 3 of 6 

the summary statistics. In this case, too, the information presented to the HSRB was 

correct. 

(4) The AaiH for 3 subjects was reported incorrectly in the study report’s Appendix K. The 

AaiH values were correct for these same subjects in study Tables 13 and 14. EPA used 

the correct values in its statistical analysis reported in the EPA Science Review and 

presented to the HSRB. 

(5) Dr. Popendorf suggested at the HSRB meeting further investigation of the air sampling 

results taking sampling time into account. If Dr. Popendorf is considering further 

analysis himself, he will need the attached tables with corrected information for mopping 

time by subject. He should also note that air sampling pumps were turned on before 

mopping began and left on during breaks, so the pump time reported in Appendix K 

differs from the mopping time reported in the attached tables. 

Attachments: 

Table 2. Summary (Empirical) of Dermal and Inhalation Results for Mop—Long Pants, Longsleeved Shirt, Shoes/socks, and No Gloves. (Corrected) 

Table 3. Summary (Empirical) of Dermal Results for Mop—Long Pants, Short-sleeved shirt, 

Shoes/socks, and No Gloves. (Corrected) 

Table 4. Summary (Empirical) of Dermal Results for Mop—Short Pants, Short-sleeved shirt, 

Shoes/socks, and No Gloves. (Corrected)
Table 2. Summary (Empirical) of Dermal and Inhalation Results for Mop—Long Pants, Long-sleeved Shirt, Shoes/

Cluster Subject 

Order 

Subject 

Number ID 

Task 

Duration 

(minutes) 

Surface 

Area 

(sq ft) 

Number Buckets 

Pounds ai 

Handled 

Dermal 

Exposure 

(μg) 

Inhalation

Exposure 

(μg/m3) 

Derm

(mg/lb 

MW-01 M13 53 1884 3 0.00308 40.7 0.413 13.MW-02 M6 85 5155 6 0.00669 42.8 0.334 6.4 MW-03 M12 45 4997 3 0.00584 136.3 0.333 23.MW-04 M28 59 5050 4 0.00538 289.4 0.209 53.MW-05 M15 67 4189 5 0.00556 191.8 0.437 34.MW-06 M27 31 3324 2 0.00419 75.7 0.292 18.

Mean 57 4100 4 0.00513 129 0.336 24.

1 

Std 19 1291 1 0.00129 98 0.083 17.

MW-07 M8 90 6688 6 0.00556226 66.9 0.123 12.MW-08 M24 79 14191 5 0.01833364 154.3 0.107 8.4 MW-09 M2 69 4952 5 0.00406091 66.9 0.108 16.MW-10 M4 63 8295 4 0.0061509 162.7 0.242 26.MW-11 M10 51 4390 4 0.00546085 112.3 0.216 20.MW-12 M21 38 5884 3 0.00482371 134.3 0.128 27.

Mean 65 7400 5 0.00740 116 0.154 18.

2 

Std 19 3599 1 0.00540 42 0.0592 7.8 

MW-13 M7 89 6161 6 0.00838418 288.3 0.273 34.MW-14 M18 79 5362 6 0.00703495 116.5 0.391 16.MW-15 M26 69 4339 5 0.00740312 365.2 0.431 49.MW-16 M14 59 5425 4 0.00699086 70.3 0.257 10.MW-17 M20 49 4989 4 0.00528448 79.2 0.249 15.MW-18 M1 38 4008 3 0.00392864 95.9 0.195 24.

Mean 64 5047 5 0.00650 169 0.299 25.

3 

Std 19 783 1 0.00161 125 0.091 14.

Mean 62 5516 4 0.00634 138 0.263 22.

Std 18 2553 1 0.00328 92 0.110 13.

Median 61 5023 4 0.00556 114 0.253 19.

Geo Mean 59 5094 4 0.00585 114 0.239 19.

Overall 

95th%tile 89 9179 6 0.00988 301 0.432 50.

Page 4 of 6 
Table 3. Summary (Empirical) of Dermal Results for Mop—Long Pants, Short-sleeved shirt, Shoes/socks, 

Cluster Subject Order Subject Number ID Task Duration (minutes) Surface Area (sq ft) Number of Buckets Pounds ai Handled U

MW-01 M13 53 1884 3 0.00308 MW-02 M6 85 5155 6 0.00669 MW-03 M12 45 4997 3 0.00584 MW-04 M28 59 5050 4 0.00538 MW-05 M15 67 4189 5 0.00556 MW-06 M27 31 3324 2 0.00419 

Mean 57 4100 4 0.00513 

1 

Std 19 1291 1 0.00129 

MW-07 M8 90 6688 6 0.00556 MW-08 M24 79 14191 5 0.01833 MW-09 M2 69 4952 5 0.00406 MW-10 M4 63 8295 4 0.00615 MW-11 M10 51 4390 4 0.00546 MW-12 M21 38 5884 3 0.00482 

Mean 65 7400 5 0.00740 

2 

Std 19 3599 1 0.00540 

MW-13 M7 89 6161 6 0.00838 MW-14 M18 79 5362 6 0.00703 MW-15 M26 69 4339 5 0.00740 MW-16 M14 59 5425 4 0.00699 MW-17 M20 49 4989 4 0.00528 MW-18 M1 38 4008 3 0.00393 

Mean 64 5047 5 0.00650 

3 

Std 19 783 1 0.00161 

Mean 62 5516 4 0.00634 

Std 18 2553 1 0.00328 

Median 61 5023 4 0.00556 

Geo Mean 59 5094 4 0.00585 

Overall 

95th%tile 89 9179 6 0.00988 

Page 5 of 6 
Page 6 of 6 

Table 4. Summary (Empirical) of Dermal Results for Mop—Short Pants, Short-sleeved shirt, Shoes/socks, 

Cluster Subject Order Subject Number ID Task Duration (minutes) Surface Area (sq ft) Number Buckets Pounds ai Handled Dermal Exposure (μg) 

MW-01 M13 53 1884 3 0.00308 82 MW-02 M6 85 5155 6 0.00669 3690 MW-03 M12 45 4997 3 0.00584 569 MW-04 M28 59 5050 4 0.00538 565 MW-05 M15 67 4189 5 0.00556 253 MW-06 M27 31 3324 2 0.00419 103 

Mean 57 4100 4 0.00513 877 

1 

Std 19 1291 1 0.00129 1395 

MW-07 M8 90 6688 6 0.00556 698 MW-08 M24 79 14191 5 0.01833 493 MW-09 M2 69 4952 5 0.00406 227 MW-10 M4 63 8295 4 0.00615 232 MW-11 M10 51 4390 4 0.00546 400 MW-12 M21 38 5884 3 0.00482 198 

Mean 65 7400 5 0.00740 375 

2 

Std 19 3599 1 0.00540 196 

MW-13 M7 89 6161 6 0.00838 789 MW-14 M18 79 5362 6 0.00703 440 MW-15 M26 69 4339 5 0.00740 505 MW-16 M14 59 5425 4 0.00699 245 MW-17 M20 49 4989 4 0.00528 152 MW-18 M1 38 4008 3 0.00393 403 

Mean 64 5047 5 0.00650 422 

3 

Std 19 783 1 0.00161 222 

Mean 62 5516 4 0.00634 558 

Std 18 2553 1 0.00328 807 

Median 61 5023 4 0.00556 401 

Geo 

Mean 59 5094 4 0.00585 358 

Overall 

95th%tile 89 9179 6 0.00988 1224